Differential-flotation process for mixed sulphide ores



Patented Oct. 16, 1928.

UNITED STATES PATENT OFFICE.

KOJIRO KAWAMURA, F TOKYO-EU, JAPAN, ASSIGNOR or ONE-HALF TO YOSHIMATSU YoKoYAMA, on KANAZAWA, JAPAN.

DIFFERENTIAL-FLOTATION PROCESS FOR MIXED SULPHILDE ORES.

No drawing.

My invention relates to the differential flotation process characterized in that anhydrous cromic acid is used in the flotation process to separate the mixed sulphide ore 6 containing several sulphide minerals, e. g. iron pyrite, chalco-pyrite, zinc blend, etc, the action of anhydrous cromic acid efi'ecting to stop provisionally the fioatage of i chalco-pyrite and iron-pyrite, while zinc 0 blende alone floats up beforehand; has for its object the economical differential separation of the valuable minerals contained.

.But, when the impure anhydrous cromic acid common in the market is to be used for this object, it has to be mixed up with proper quantity of the alkaline salts, for it usually contains sulphuric acid more or less.

The quantity of added alkali must be in such a proportion that the sulphuric acid present is neutralized; this must be found by test to prevent an over-addition of alkali which would form bichromate salts with the chromic acid present.

My invention consists in the rocess in which chalco-pyrite and zinc blendh are sep- "arated and picked out respectively and very economically out of the mixed sulphide ore, which hitherto existing processes, the dress ing or the flotation, have been unable to attain. For example, the result of the differential flotation process, hitherto commonly known reagents being used, is as'the following Table No. I.

trated in the above table, zinc blende floats up always with the other sulphide minerals so that these valuable minerals could not be economically separated. Moreover, in the other existing differential flotation process in which a certain chemical, or chemicals, is, or are, used as the reagent, the floatage of iron pyrite is provisionally somewhat stopped, while most of the chalco- Application filed 121110.317 18, 1526. Serial No. 82.125.

fectly. One of the experimental results in the process is as the followlng Table No. II.

Table No. II.

fgfi Grade Extraction I l i l Gr Cu Fe Zn iAmountl Cu Fe Zn E i Per Per For. I Per l Ptr PH cmlicentvce'nt Percent! cent cent Irmt 0ngma1ore 400 9. 13.24. 77 2o. 43 100. 001100. 00100. 00100. 00 Concentrate- 137.8 2.0a; so 57.62 34.45 7.86. 5.37. 80.27 Mingling. 11.1 960 11013261 8.27; 8.71! 5.0%;1091 Talllng 229.1|l3. 30138.43 3.81, 5128i 83.43] 88.95, 8.82

In the above table, the middling is to be treated again being placed back into the original ore, at the practical operation. As illustrated in the above table, if-anhydrous aromic acid is used as the reagent, both chalco-pyrite and iron pyrite are affected very much and their fioatage is stopped almost entirely, while most of the zinc blende being ail'ected little floats up into the concentrated mineral, resulting in the ratios of zinc grade 57.62% and extraction percent 80.27%. The present invention hereby succeeds in the separation and picking out between chalco-pyrite and zinc blende almost to a perfect degree, which have hitherto been taken for almost impossible. Anhydrous cromic acid to be used for this object,

a d r- 1 1-. 1 ex on s 10m 100 0 100.00 of the original ore.

lVhen galena is also contained in the original ore it is understood that the separation is carried out by the process of specific gravity concentration.

I claim against that The process of differentially floating ores comprising adding crude commercial anhydrous chromic acid with alkali to neutralize sulphuric acid therein to a pulp con- 5 taining a mixture of sulphide minerals, said chronnc acid being added in quantity sufficient to inhibit flotation of cupriferous and ferric sulphides without afiecting zinc sulphide, and then subjecting the mixture to flotation.

In testimony whereof, I have hereunto set my hand.

KOJIRO KAVAMURA. 

